The 1985 American League Championship Series was played between the Kansas City Royals and the Toronto Blue Jays from October 8 to 16. Major League Baseball decided to extend the Championship Series in both leagues from its best-of-five (1969–1984) to the current best-of-seven format starting with this year, and it proved pivotal in the outcome of the ALCS. The Blue Jays seemingly put a stranglehold on the Series, earning a three games to one lead over the Royals after four games. However, Kansas City staged an improbable comeback, winning the next three games to win the American League Championship Series four games to three. The Royals would proceed to defeat their cross-state rivals, the St. Louis Cardinals, in the World Series four games to three.

The American League Championship Series (ALCS), also known as the American League Pennant, is a best-of-seven playoff and one of two League Championship Series comprising the penultimate round of Major League Baseball's (MLB) postseason. The winner of the ALCS wins the AL pennant and advances to the World Series, MLB's championship series, to play the winner of the National League's (NL) Championship Series. The ALCS began in 1969 as a best-of-five playoff and used this format until 1985, when it changed to its current best-of-seven format.